Regulation of gene expression in Bacteria

[Lucanus cervus]

Hi,


I'm learning about the regulation of the lactose system in bacteria and came across the following:

The lac promotor and repressor are commonly used in expression cloning vectors.

But now my question is: Why?

Is it because they are thouroughly studied and well know, or because the negative control is useful to be able to express large amounts of something only in a specific stage of development in your experiment?

Or something else?


Thanks in advance

Sam

[canalon]

convenient, and widely available mostly. Plus there are plenty of bacteria that have been modified to allow different things to be done (change in regulation etc.. ) and to top it off, the expression of native lacZ can easily be tracked by a colorimetric reaction.

But besides that, the system has no inherent superiority. It is jus so well known and widely used that plenty of neat or simple tricks can be done. And no fear of patenting the system

[Lucanus cervus]

ok thank you

It was "the expression of the lacZ gene that can be easily tracked by a colorimetric reaction" explanation that I was looking for.

I've looked it up in "Introduction to genetic analysis" and it says that the artificial substrate X-gal is used, which can be converted/broken down by B-Galactosidase (the product of the lacZ gene), which results in a blue dye.


Again, thanks for the quick answer